Electric-motor regenerative pumps have heretofore been proposed and employed in automotive engine fuel delivery systems. Pumps of this character typically include a housing adapted to be immersed in a fuel supply tank with an inlet for drawing liquid fuel from the surrounding tank and an outlet for feeding fuel under pressure to the engine. The electric motor includes a rotor mounted for rotation within the housing and connected to a source of electrical power for driving the rotor about its axis of rotation. An impeller is coupled to the rotor for corotation with the rotor, and has a circumferential array of vanes about the periphery of the impeller. An arcuate pumping channel, with an inlet port and an outlet port at opposed ends, surrounds the impeller periphery for developing fuel pressure through a vortex-like action on the liquid fuel between the Dockets formed by the impeller vanes and the surrounding channel. One example of a fuel pump of this type is illustrated in U.S. Pat. No. 5,257,916.
A general object of the present invention is to provide an electric-motor regenerative fuel pump of the described character that achieves improved venting of fuel vapors and thereby helps reduce vapor lock and stall at the engine, and/or that provides improved fuel transition at the inlet and outlet ports of the pump to improve pumping efficiency and reduce noise. Another object of the present invention is to provide an improved and economical fuel pump of the described character and method of manufacturing the same.